1. Field of the Invention:
This invention relates to a multi-light-adjusting type camera arranged to project light from a flash light emitting part to an object to be photographed, to measure the reflected light of the projected light in a plurality of areas and to determine, according to the results of light measurement, the amount of light to be emitted from the flash light emitting part.
2. Description of the Related Art:
Many of cameras in the market are of the light-adjusting type determining the amount of flash light according to the measured value of intensity (quantity) of a reflected light obtained by tentatively projecting light from a flash light emitting part to an object and by measuring the reflection light thus obtained.
Most of them adjust the light by measuring reflected light with a single light measuring sensor in such a way as to attach weight to the central part of an image plane. Therefore, an adequate degree of exposure can be obtained if a main object to be photographed is located in the central part of the image plane in a suitable size. However, in cases where the main object is not located in the central part of the image plane or where the object is too small relative to the size of the image plane, it is hardly possible to obtain an adequate degree of exposure because of the adverse effect of the light quantity of a background.
To solve this problem, a multi-light-adjusting type camera has been proposed in Japanese Laid-Open Patent Application No. SHO 60-108827. This camera is arranged to determine and control the amount of flash light to be emitted by arranging a plurality of light measuring sensors and by variably controlling them. This camera, however, necessitates the photographer to manually set a weight attaching part of the image plane. The photographer is thus required to perform a troublesome operation.
Another camera which has been disclosed in Japanese Laid-Open Patent Application No. SHO 55-135823 is arranged as follows: The light of the object is measured without flashing and also with flashing. The measured light values thus obtained are compared with each other. Then, an area having the image of an object which is located nearest the camera is selected according to the result of comparison. The amount of flash light to be emitted is controlled on the basis of the measured light value of that area. In accordance with this method, the degree of exposure becomes apposite to the nearest object. However, it becomes inadequate if a main object is not the nearest object. In addition to this, the method does not take into consideration any balanced relation to the background. Further, in accordance with this method, a flash light emitting action must be performed once before photographing, thus necessitating additional consumption of the electric energy of the power source.
Further, a method of measuring the light values of a plurality of areas of the image plane and making an exposure on the basis of the measured light value of one of the areas corresponding to a distance measuring area has been disclosed in U.S. Pat. No. 4,796,043. However, this prior art disclosure includes nothing about any arrangement to measure the light of an object illuminated by flash light and to control the amount of flash light according to the result of measurement.
Most of the cameras of these days are arranged to have an automatic focusing (hereinafter referred to as AF) mode including a mode in which an in-focus state is held unchanged once the lens is correctly focused (hereinafter referred to as one-shot mode). In the one-shot mode, it is possible to perform photographing, for example, by performing distance measurement by temporarily bringing a main object to a central part of the image plane and, after that, by readjusting the framing of the shot. In such a case, however, an exposure cannot be made appositely to the main object if it is not the nearest object. Even if the main object is located nearest the camera, a picture taken in accordance with the method does not always have the object and the background thereof in a well balanced state.
The cameras of these days include some cameras having such an AF mode that is arranged as follows: The distance measurement is repeatedly performed and the movement of the object is predicted in such a way as to have the lens focused on the object at the time of shutter release on the basis of current and past measured distance values (hereinafter referred to as a predictive servo mode). However, there has been proposed no method for exposure control over flash photography to be performed in the predictive servo mode with balance between the object and the background taken into consideration.